In the punch and die art and particularly in the field of high-speed automated forming and punching equipment for punching and forming sheet material, e.g., sheet metal and especially in the case of automated turret punch presses, the punch presses are operated by computer to perform a series of punching or forming operations sequentially. These punch presses which by themselves form no part of the present invention are typically provided with an upper turret and lower turret that rotate and are indexed intermittently between punching operations. The turrets may, for example, hold as many as a dozen or more separate punches that are used in sequence for performing given operations. The distance between the replaceable upper metal forming insert or punch and the die which is held by the lower turret can be referred to as the “feed gap.” The feed gap is an important factor because the workpiece may have one or more upward or downward projections which must be cleared by the punch insert when the turrets rotate or the workpiece is repositioned. Thus, if a projection extends an inch above the top of the workpiece, the lower end of the punch insert must be slightly more than an inch above the workpiece in order to clear the extension when the turret is rotated or the workpiece is repositioned. Heretofore, the height of any projection was limited by the feed gap.
In view of these and other deficiencies of the prior art, it is one object of the invention to provide an improved punch assembly having a provision for assuring that the lower or working end of the punch will not strike obstructions when moved laterally relative to the workpiece following a punching operation. It is another object of the present invention to provide an improved punch assembly that provides an effective feed gap control for changing as well as increasing the distance between the working end of the punch and the workpiece, that is to say, for increasing the feed gap.
Yet another object of the invention is to provide an improved punch assembly of the type that is suspended from a supporting flange.
Still another object of the invention is to provide an improved punch assembly which includes a circumferentially extending supporting flange with a feature for automatically retracting the upper forming tool or punch while maintaining a constant distance between the top of the punch assembly and the bottom of the punch insert.
These and other more detailed and specific objects of the present invention will be better understood by reference to the following figures and detailed description which illustrate, by way of example, but a few of the various forms of the invention within the scope of the appended claims.